The invention relates to a drive and guide means for a load to be moved comprising a pressure medium cylinder, a rodless drive piston adapted to be driven by a pressure medium in such pressure medium cylinder, at least one force transmission part extending outward through a longitudinal slot in a wall of such cylinder, a flexible sealing tape for sealing off the longitudinal slot on either axial side of the force transmission part and an anti-friction bearing arrangement serving to take up a load and/or to guide the piston, such anti-friction bearing arrangement being arranged in the housing of the pressure medium cylinder.
In the case of a known drive and guide means of this type disclosed in the German patent publication 4,332,547 A1 a load supporting anti-friction bearing arrangement is arranged in a longitudinal channel, provided in the housing of a pressure medium cylinder, extending in parallelism to the cylinder bore of such pressure medium cylinder. Owing to such parallel arrangement of the drive piston and the anti-friction bearing arrangement the housing of the pressure medium cylinder is generally extremely voluminous and it is not only necessary to have a force transmission part extending outward from the housing but also in addition a further force transmission part between the drive piston and the anti-friction bearing arrangement. This all means that entire arrangement is complicated, elaborate and expensive.
One object of the invention is accordingly to provide a drive and guide means, in the case of which the housing of the pressure medium cylinder may be designed with a smaller cross section.
A still further object of the invention is to provide such means which may be produced in a simpler, less expensive and compact form.
In order to achieve these and/or other objects appearing from the present specification, claims and drawings, in the present invention the anti-friction bearing arrangement is arranged within the cylinder space of the pressure medium cylinder in or on the drive piston.
The advantage of the arrangement of the invention is more especially that only a single longitudinal duct is provided in the housing of the pressure medium cylinder, that is to say the cylinder bore itself. This means that there is a substantially more compact form of design. Since the drive piston or, respectively, its anti-friction bearing arrangement takes up the load and as a result bears against the cylinder wall, external load or force resistant guides are now not necessary. There is accordingly no longer any danger of an external guide transmitting forces to the drive piston, which would impair its function. In fact only a single slot guide in the housing of the pressure medium cylinder is required, unlike the case of the prior art, wherein two through slots are necessary. The design of the force transmission part is accordingly substantially simplified. Moreover, the entire assembly operation becomes simpler and less expensive.
The measures recited in the claim render possible advantageous further developments and improvements in the invention.
The anti-friction bearing arrangement preferably possesses wheels or rollers and/or balls running on the cylinder bore wall.
In accordance with a first advantageous development of the invention the anti-friction bearing arrangement has an axial row of wheels or rollers inclined in opposite directions of pivot in relation to the force acting on the piston. In this respect the wheels or rollers are advantageously oppositely inclined so that the transfer of force is as even as possible.
An other advantageous feature of the invention is such that the anti-friction bearing arrangement possesses an axial row of pairs of wheels or rollers, whose axes of rotation are set perpendicularly to the direction of motion of the drive piston and perpendicularly to the direction of the force acting on the piston.
The anti-friction bearing bodies of the bearing arrangement are rotatably placed in corresponding recesses in the drive piston or a bearing arrangement connected with it and extend out from the recesses at those points, at which the drive piston bears against the cylinder bore wall. This means that there is an excellent transfer of force by a relatively small number of anti-friction bearing bodies.
To stabilize the position of the piston and to resist pivoting moments the anti-friction bearing arrangement preferably comprises at least one supporting rolling body which is rotatably mounted in the drive piston or in a bearing arrangement connected with it, such supporting rolling body being adapted to run along part of the cylinder wall opposite to the direction of the force acting on the drive piston.
The anti-friction bearing arrangement is preferably arranged between the two piston seal regions sealing off the drive piston on either side. In this respect it is possible for the anti-friction bearing arrangement to possess two regions which are connected together, on which one respective region of the two-part force transmission part is arranged. In this respect a respective piston sealing region of the drive piston is preferably arranged of the two terminal regions of the bearing arrangement for the anti-friction bearing arrangement so that a symmetrical modular arrangement is produced which may be assembled as desired at any time.
The at least one force transmission part connected with the drive piston may, in accordance with an advantageous form of the invention, be designed in the form of a suspension device for the load and extend vertically downward out of the longitudinal slot. In the case of such a design it is for instance possible for a curtain or a sliding wall or window to be suspended, which may then be pneumatically along a long distance.
In order to prevent a pivoting of the piston and undesired friction of the force transmission part in the longitudinal slot such force transmission part possesses a plain or anti-friction bearing guide for dealing with forces occurring on pivoting of the drive piston. Such guide is preferably arranged at the longitudinal slot.
Further advantageous developments and convenient forms of the invention will be understood from the following detailed descriptive disclosure of embodiments of the accompanying drawings.